Encyclopedia of Global Resources part 131 pdf

dioxide are added to extensively altered olivine- or pyroxene-rich igneous rocks, and when water and sil- ica are added to altered carbonate rocks, talc forms. Talc is also found in crystalline schists. The mineral is found mostly in mountainous regions, with China, South Korea, and Japan as the chief sources. His- torically, the Pyrenees Mountains of France were a major source of talcandcontributedtothebeginning of the cosmetic’s industry in that country. History Talc has been used since ancient times for carved and engraved ornaments and utensils. American Indians used steatite for making bowls, pots, and stoves, and Eskimos used it forsculptures. Talc hasbecomeanim- portant ingredient in many commercial products. Obtaining Talc Generally, talc is obtained through open-pit mining techniques. In his book Functional Fillers for Plastics (2005), Marino Xanthos outlines the seven-to-eight- step process for obtaining talc through open-pit mining. First, the overburden is removed, thus exposing the talc. The talc is then shoveled out of the mine in order to be crushed. Then it is categorized by bright- ness and content. The talc is ground to break it down further. For most talc this is the final procedure. How- ever, high-grade talcs, such as those used in the phar- maceutical industry, require treatment with various chemical compounds. Uses of Talc In the ceramics industry, talc is used in tableware, electrical porcelain, and glazed wall tiles. In paints, talc is used as a extender and as a pigment. It is used as a filler in paper, rubber, insecticides, lubricants, and leather salves. In cosmetics, it is used in toilet pow- ders, soaps,andcreams, withits extremesoftness lead- ing toits use as talcumpowder and facepowder. (With revelations that talc in cosmetics might be linked to lung, ovarian, and skin cancers, many consumers began to avoid talc-containing products.) Massive slabs of talc are used for acid-proof laboratory tables, sinks, sanitary appliances, acid tanks, electrical switch- boards, mantels, and hearthstones. Because it is a poor conductor of electricity and heat, it is used as in- sulation and as a roofing material. Alvin K. Benson See also: Ceramics; Hydrothermal solutions and mineralization; Japan; Magnesium; Metamorphic processes, rocks, and mineral deposits; Minerals, structure and physical properties of; Petrochemical products; Rubber, natural; Silicates; Silicon; United States. 1206 • Talc Global Resources Ceramics 31% Paint 19% Paper 21% Plastics 5% Roofing 8% Rubber 4% Other 12% Source: Mineral Commodity Summaries, 2009 Note: Data from the U.S. Geological Survey, .U.S.GovernmentPrinting Office, 2009. “Other” includes cosmetics. U.S. End Uses of Talc Talc is the softest mineral on the Mohs hardness scale. (USGS) Tantalum Category: Mineral and other nonliving resources Where Found Tantalum is moderately uncommon and is about as abundant as uranium in the Earth’s crust. It is almost always found in minerals that also contain niobium and is most commonly found in granite and minerals derived from granite. Tantalum ores are most abundant in Africa and South America. The world’s major producers, in descending order, are Australia, Brazil, Ethiopia, Canada, and Rwanda. Other producers include Burundi, the Democratic Republic of the Congo, Nigeria, Uganda, and Zimbabwe. Primary Uses The most important uses for tantalum are in the manufacturing of capacitors (accounting for more than 60 percent of use in the United States) and in making corrosion-resistant equipment for chemistry labora- tories. Tantalum is also used in various electronic devices and in surgical equipment. Technical Definition Tantalum (abbreviated Ta), atomic number 73, belongs to Group VB of the periodic table of the elements and resembles niobium (also known as columbium) in its chemical and physical properties. It has one naturally occurring isotope and an atomic weight of 180.95. Pure tantalum is a hard, dense, silver-gray metal. Its density is 16.65 grams percubic centimeter; it has amelting point of 2,996° Celsius and a boiling point of 5,427° Celsius. Description, Distribution, and Forms Tantalum is a fairly rare element resembling niobium. It occurs as the oxide in minerals containing niobium. A small amount of the free metal is found in the former Soviet Union. Tantalum is used in capacitors and chemical equipment. History Tantalum was discovered by the Swedish chemist Anders Gustaf Ekeberg in 1802. Because tantalum is so similar to niobium, the two elements were thought to be identical until 1844, when the German chemist Heinrich Rose proved they were different. Tantalum was briefly used for lightbulb fila - ments during the early twentieth century until it was replaced by tungsten. Obtaining Tantalum The most difficult problem in obtaining tantalum is in separating it from the very similar niobium found in its ores. The most common method is known as liquid-liquid extraction. Theore is treated withhydro- fluoric acid, which dissolves the tantalum and niobium compounds. This solution is then treated with an organic solvent. This solvent extracts the tantalum compound at a low level of acidity. At a higher acidity the niobium compound is extracted. The tantalum compound obtained by this method may be electrolyzed in a solid form at about 900° Cel- sius to produce pure tantalum powder. This powder may also be obtained by treating the tantalum compound with metallic sodium. The powder may be transformed into tantalum metal by heating it in a vacuum. Global Resources Tantalum • 1207 Electronic components 70% Machinery 20% Transportation 6% Other 4% Source: Historical Statistics for Mineral and Material Commodities in the United States U.S. Geological Survey, 2005, tantalum statistics, in T. D. KellyandG.R.Matos,comps., ,U.S.Geological Survey Data Series 140. Available online at http://pubs.usgs.gov/ds/2005/140/. U.S. End Uses of Tantalum Uses of Tantalum Tantalum is used to manufacture equipment for the chemical industry because it is extremely strong and does not react with most chemicals. It has also been used in surgical devices because it does not react with body tissues. Another use is in the manufacture of capacitors, electronic devices that store electric energy. Tantalum capacitors have a greater ability to store energy than any other capacitors of the same size and are thus used in miniaturized components. Tantalum compounds have also been used to manufacture tools used to cut very hard metals, to manufacture special kinds of glass, and as catalysts for various chemical re- actions. Rose Secrest Web Sites Natural Resources Canada Canadian Minerals Yearbook, 1994: Tantalum http://www.nrcan.gc.ca/smm-mms/busi-indu/cmy- amc/content/1994/60.pdf WebElements Tantalum: The Essentials http://www.webelements.com/tantalum/ See also: Granite; Metals and metallurgy; Niobium; Oxides; Tungsten. Tar sands. See Athabasca oil sands; Oil shale and tar sands Taylor Grazing Act Categories: Laws and conventions; government and resources Date: 1934 In the early 1930’s, with much of the federal land in the West suffering from overgrazing and drought, the Taylor Grazing Act imposed regulations on the use of the remaining public domain of the American West. Background With the United States in the throes of the Great Depression, the public lands of the American West suffered from severe drought and overgrazing. As Congressman Edward Taylor of Colorado warned his colleagues, “We are rapidly permitting the creations of small Sahara Deserts in every one of the Western states today.” Until 1934, Western stockmen grazed animals on federal lands without the need of permis- sion and regulation. In the laissez-faire economic atmosphere of the late 1920’s, President Herbert Hoover’s Commission on theConservation andAdministration of thePublic Domain had recommended that the remaining public domain be turned over to the states with the federal government retaining title to mineral lands. Soon the Depression intervened, however, and concerned westerners channeled their energies into working with federal bureaucrats to shape an acceptable plan for managing those millions of acres of federal lands outside the purview of the National Park Service, Na- tional Forest Service, and other federal agencies. The plan was named after Taylor, whose home district in western Colorado contained a high percentage of federal land.If a veteran congressman such asTaylor could see the benefit of federal regulation, most westerners could also. Even old stockmen who had previ- ously opposed the federal presence as a matter of prin- ciple gave grudging approval to Taylor’s legislation. Provisions The bill ended the free use of the public domain. Homesteading would no longer be permitted. Thirty- two millionhectares of western land wouldbe given to a new federal agency, the U.S. Grazing Service, under the Department of the Interior.Local grazing districts were established, and policies would be set by the ranchers themselves. Users would pay a nominal fee to rent the land for ten-year periods, with a portion of the proceeds goingto support conservation projects. Impact on Resource Use The Taylor Grazing Act firmly upheld the economic status quo in the public-land West by ordering that “preference” be given in the issuance of grazing per- mits to “landowners engaged in the livestock busi- ness” and those living near or in the grazing district. In 1936, the act was amended, increasing the total acreage under its domain to 58 million hectares. Be- cause the Taylor Grazing Act was founded and ad- ministered by westerners during an era of economic duress, its implementation was relatively free of con - troversy, but several critics of its authority soon ap - 1208 • Taylor Grazing Act Global Resources peared. Senator Pat McCarran, a Nevada Democrat, tried to challenge the system of uniform grazing fees. In 1946, Wyoming Republican senator Edward V. Robertson harked back to the Hoover Commission by calling for a “return” of all federal lands to thestates, a strategy echoed in the late 1970’s by the so-called Sagebrush Rebellion. McCarran and other western critics of the Grazing Service succeeded in trimming its budget during World War II and forcing its merger with the General Land Office in 1946. The new agency, the Bureau of Land Management, would administer the public domain in the years ahead. Steven C. Schulte See also: Bureau of Land Management, U.S.; Dust Bowl; Ickes, Harold; Public lands; Sagebrush Rebel- lion. Tellurium Category: Mineral and other nonliving resources Where Found Tellurium is uncommon but widely distributed in the Earth’s crust. Ithas been foundin small amountsas an uncombined element but is most often found in various compounds. These compounds occur in sulfide deposits or in ores of gold, copper, and lead. Primary Uses Tellurium is used in small amounts to improve the properties of other metals. Tellurium compounds are used to manufacture thermoelectric devices. Technical Definition Tellurium (abbreviated Te), atomic number 52, belongs to Group VIA of the periodic table of the elements and resembles selenium in its chemical and physical properties. It has eight stable isotopes and an average atomic weight of 127.6. Pure tellurium exists as brittle, silver-white crystals or as a dark gray or brown powder. Its density is 6.24 grams per cubic centimeter; it has a melting point of 449.8° Celsius and a boiling point of 989.9° Celsius. Description, Distribution, and Forms Tellurium is a widely distributed element resembling selenium. It usually occurs in compounds with cop - per, lead, silver, gold, iron, or bismuth. The most im - portant sources of tellurium are ores mined for copper, lead, and gold. The most important producers of tellurium are Canada, the western United States, and Peru. Tellurium is nonrenewable, and investigations into the recovery of tellurium from goldand lead-zinc ores is ongoing. History Tellurium wasdiscovered in 1782 bythe Austrian mining inspector Franz Joseph Müller von Reichenstein. It was not isolated as a free element until 1798 and not used for practical purposes until the middle of the twentieth century. Obtaining Tellurium Tellurium is usually obtained as a by-product of copper production. After copper is removed from processed ore by electrolysis, the remaining material contains tellurium as well as silver, gold, and selenium. The tellurium is separated out by treating the material with a base, then neutralizing it. This produces impure tellurium dioxide. This compound can be purified by repeatedly dissolving it and recrystalliz- ing it. Free tellurium metal may be obtained by electrolysis. Uses of Tellurium Tellurium is added to steel to improve its machinability and added to copper to create an alloy with good machinability and high electrical and thermal conductivity. It also increases the ductility of alumi- num alloys, the hardness and strength of tin alloys, and the resistance to corrosion of lead alloys. Rubber may betreated with tellurium toimprove its agingand mechanical properties. Tellurium has also been used alone or with platinum as a catalyst for chemical reac- tions. Tellurium compounds are used in thermoelectric devices. Lead telluride is used to make devices that produce electricity when heated. Bismuth telluride is used to manufacture devices that transfer heat when electricity passes through them. Tellurium is most important as a steel additive and secondarily as an alloy in copper (to improve its machinability while maintaining conductivity), lead (to dampen vibration and lessen metal fatigue), and cast iron (to reduce depth of chill). It is also used in photoreceptors, in blasting caps, in thermal cooling devices, and as a catalyst in the production of syn - Global Resources Tellurium • 1209 thetic fibers. Tellurium has been added to glass and ceramics to alter the pigments of these products. An increasingly important application is in the manufacture of solar cells, accounting for an increased demand for high-grade tellurium. Although tellurium is a toxic substance, serious poisonings are rare. Symptoms caused by tellurium include nausea, headache, sleepiness, and dry mouth. The most distinctivefeature of tellurium ingestion isa strong garlic breath odor, which may persist for several days. Tellurium toxicity rarely requires treatment. Vitamin C has been used to treat the breath odor. Rose Secrest Web Sites Natural Resources Canada Canadian Minerals Yearbook, 2005: Selenium and Tellurium http://www.nrcan.gc.ca/smm-mms/busi-indu/cmy- amc/content/2005/50.pdf U.S. Geological Survey Mineral Information: Selenium and Tellurium Statistics and Information http://minerals.usgs.gov/minerals/pubs/ commodity/selenium/ See also: Alloys; Metals and metallurgy; Selenium; Sulfur. Tennessee Valley Authority Category: Organizations, agencies, and programs Date: Established May 18, 1933 The Tennessee Valley Authority, created primarily for navigation and flood control of the Tennessee River, soon became the major producer of electricity for, and spurred the economic growth of, a seven-state area. Background The Tennessee Valley Authority (TVA) is an indepen- dent agency of the executive department of the United States government. Three directors are appointed by the president for staggered nine-year terms to administer theagency and itsnineteen thousand employees. The main offices are in Knoxville and Chattanooga, Tennessee. The concept of encouraging economic growth in the southeastern portion of the United States by making the Tennessee River more navigable began in 1827, more than one hundred years before the estab- lishment of the Tennessee Valley Authority, when Congress appropriated funds to help survey Muscle Shoals on the Tennessee River in northern Alabama. Although the canal project that resulted from that survey was a failure, the idea of taming the river was permanently implanted in the minds of southern leaders. Almost a century later, in 1913, the next step was taken when Hale’s Bar Damwas completed on the river near Chattanooga,Tennessee. This damtamed a turbulent section of the river nicknamed the Suck. When Wilson Dam made Muscle Shoals passable in 1926, the way was prepared for major development of the entire Tennessee Valley. The beginning of the Great Depression in 1929 made the need for that development more acute. George W. Norris, a progressive Republican senator from Nebraska, led the drive for public development of the Tennessee Valley and earned the infor- mal title “father of TVA.” The bill to establish the Tennessee Valley Authority was one of the first products of President Franklin D. Roosevelt’s New Deal. It was passed and signed in May, 1933. The first dam built by the TVA was a storage dam on the Clinch River. It was completed in 1936 and named for Sena- tor Norris. Charges by private industry that the TVA was unconstitutional were rejected by the Supreme Court in 1939. During World War II, electricity produced by the TVA played a crucial role in manufacturing for national defense. Facilities at Oak Ridge, Ten- nessee, were a major component of the Manhattan Project, which produced the atomic bomb. The facilities operated primarily on TVA electricity. Impact on Resource Use The fifty damsoperated directly by theTVA have been instrumental in flood control in the Tennessee Valley and in the larger Ohio River and Mississippi River system. The nine dams on the main stream of the Tennes- see River also created a 1,046-kilometer-long navigation channel from Knoxville, Tennessee, to Paducah, Kentucky. Electricity is produced by twenty-nine of the damsand by elevencoal-burning steamplants and two nuclear plants operated by the TVA. The power is distributed over an area of about 207,000 square kilo - meters. TVA lakes provide recreational facilities for about sixty million people each year. Fertilizer devel - 1210 • Tennessee Valley Authority Global Resources opment, nuclear energy research, conservation of natural resources, and many other projects have been part of the work of the Tennessee Valley Authority. Glenn L. Swygart Web Site Tennessee Valley Authority http://www.tva.gov/ See also: Coal; Conservation; Electrical power; Floods and flood control; Hydroenergy; Nuclear energy; Nu- clear Regulatory Commission; Roosevelt,Franklin D. Textiles and fabrics Category: Products from resources The term “textile” is normally used interchangeably with the terms “cloth” and “fabric.” A textile is a knitted, woven, or nonwoven cloth material. The term is also applied to fiber and yarn intended for fabric production. Textiles typically use cotton, flax, ramie, hemp, jute, and other sources of cellulosic plant fiber; the fur of sheep, goats, llamas, and several other animals; and fiber from silkworms, gold, silver, and rubber trees. Background All textiles are made through the use of fibers: thin strands of natural or artificial material. A fiber is a threadlike strand, usually flexible, and is capable of being spun into yarn. About forty different fibers are of commercial importance. While textiles are primarily made from yarn, they are also made by felting, which is the process of pressing steamed fibers together to make cloth. All knitted and woven textiles are made from yarn, while fibers alone are used to produce nonwoven cloth. The invention of spinning machines and weaving machines during the In- dustrial Revolution greatly increased production and boosted the demand for fibers. The textile industry has created a tremendous di- versity of products available for use in clothes, home furnishings, and industrial applications. These products are fabricated from natural resources, such as animals, plants, and minerals, as well as from synthetic compounds. The major classifications of fibers by source are natural and artificial. Natural fibers are those fibers found in nature, such as those from ani - mals and plants; textiles represent a major use of the world’s plant and animal resources. Artificial fibers are those fibers manufactured in a laboratory. History About 5000 b.c.e., in Egypt’s Nile Valley, the flax plant was grown and processed into a cloth that was used to wrap mummies of Egyptian rulers. At this same time in Iraq, textiles were made from the wool of sheep. By about 3000 b.c.e., other areas of early cotton use were Switzerland, India, and Peru. China developed silkmaking by using silkworms at this time. Textiles as a commodity used in trade with other countries started around 1700 b.c.e. as this product became more developed in Asia, the Middle East, and Africa. In more recent history, the Industrial Revolution had a profound effect on the making of textiles, and textile manufacturing was established by the early 1900’s as an industry in many countries of the world. Animal Fibers Examples of animal fibers are the hair of animalssuch as sheep, goat, rabbit, fox, deer, llama, alpaca, vicuña, horse, beaver, hog, badger, sable, and camel. These are protein fibers. The silkworm also produces a protein fiber. Sheep’s wool is the major animal fiber. This soft, curly hair is usually called wool, or fleece, instead of hair. A layer of wool can be periodically sheared from the animal without ill effect. Plant Fibers A major plant fibersource is the cellulose from plants. Cellulosic fiber can be found in a plant’s leaf, stem/ stalk, seed pod, or fruit, as applicable. Piña, from the pineapple plant, is an example of a leaf fiber. Flax, jute, ramie, and hemp are fibers taken from a plant’s stem or stalk, also known as bast fibers. Cotton and ka- pok are examples of seed pod and fruit fibers. Azlon fibers are produced from proteins found in soybeans and corn. Cotton and flax are the major plant fibers. One plant source that is not cellulosic is sap from the rubber tree, which can be processed into yarn. Mineral Fibers Asbestos is a somewhat minor natural source of fiber material. Found in rock deposits, it has been used to manufacture products such as fire-resistant cloth. With the identificationof asbestosas a carcinogen,U.S. production ceased, and several other nations placed Global Resources Textiles and fabrics • 1211 similar restrictions on this mineral. Examples of other minerals and materials used to make fibers are gold, silver, iron (in steel), and glass. These materials can be drawn into thin threads and then used as decoration in garments and for support (steel mesh in tires, for example). Fiber Makeup The textile fabric that one can see and touch is composed of many individual fibers. The differences between fibers are determined by their chemical composition and individual unique structure. Molecular combinations of different elements are called compounds. Any particular (molecular) compoundalways contains thesame type and number of elements and their atoms. This gives each compound unique characteristics thatdetermine its particularend use as atex- tile. When many molecules making up a compound are connected to one another in a line, they form a linear molecule. If this linear molecule is very long, it is called a polymer. Animal hair, the living matter of plants, and some synthetic compounds all contain polymers. These long-string linear molecularcompounds are the building blocks of fibers, which can then be made into fabrics. When polymers are formed synthetically, the process is called polymerization. Only a few elements, in different combinations, make up all the natural and artificial fibers in textiles. For example, carbon, hydrogen, and oxygen, in various combinations, make up all the plant cellulosic fibers. The protein fibers contain nitrogen as well. Chlorine, fluorine, silicon, and sulfur are other elements found in some fibers. Artificial fibers may be constructed from natural polymers that have been reshaped or from synthesized polymers made through chemical processes. All fabric fibers have a characteristic length; these range fromless than1 centimeter tomore than36 meters. Arelatively short fiber rangingfrom fractionsof a centimeter to a few centimeters is known as a staple fiber. A relatively long fiber, measured in meters, is known as a filament fiber. A natural fiber is always used in the length in which it has grown. Artificial fibers, on the other hand, can be made in any length, regardless of whether they are reshaped or synthe - sized. The end-use application of the artificial fiber will determine what its optimum length should be. Artificial Fibers After the invention of artificial fibers in the late 1800’s, there was wide-ranging development of artificial fibers in the 1900’s. There are two subgroups of artificial fibers: reconstituted or altered fibers made from natural sources and fibers made from chemical compounds. Artificial fibers are produced from compounds hav- ing a wide range of chemical composition and inter- nal structure. However, this range of products can be broken down into groups of fibers that have similar composition andstructure. Ageneric name is givento each of these groups. For naturally occurring materials there are six genericfamilies: acetate/triacetate, azlon, glass fiber, metallics, rayon, and rubber. For chemically synthesized fibers there are eleven generic families: acrylic, anidex, modacrylic, nylon, nytril, olefin, polyester, saran, spandex, vinal, and vinyon. All these families are legally defined and identified. Manufac - turers making any of these products register a trade - mark name(or tradename) for theirparticular fiber. 1212 • Textiles and fabrics Global Resources Julian Hill, a research chemist with DuPont, reenacts the mid-1930’s dis- covery of nylon. (Hagley Museum and Library) Artificial Fibers from Natural Sources. De - veloped as a substitute for silk, the first artificial fiber was named rayon around 1925.Wood pulp is the major cellulose source of raw material used to produce rayon fiber. Cotton linters (a by-product of cotton production) are another source. These sources are chemically processed to extract and purify the cellulose. In regen- erating cellulose into rayon, the purified cellulose un- dergoes several chemical and mechanical treatments before beingforced througha spinneretmachine. Ac- etate and triacetate are two other artificial fibers that are based on cellulose as a raw material. Artificial Fibers from Chemicals. Chemically created fibers are known as synthetic fibers. The first step in synthesis is polymerization. Certain general production techniques are similar for fibers made from synthesized polymers. Initially, chemical compounds are combined in a closed vat called an auto- clave. Solvents are added, or heat and/or pressure is applied, to melt and polymerize the compounds. Next, this solution is forced through holes in a spinneret, a device that contains a nozzle similar to a shower nozzle. Blowing air on the solution as it exits the nozzle, or directing the spray through chemically altered water, hardens the solution into filaments. This process is called spinning. After spinning, the hardened fibers are stretched by being wound on rollers while under tension. This reduces the diameter of the fiber, simultaneously making it uniform and stronger. Variations of this general process are made for different materials and end uses. There are differences in the number of steps taken, the types of raw materials used, the spinneret nozzle hole size and shape, and the manner in which the filaments are hardened. Yarn Yarn is generally defined as a continuous strand of fibers spun together asa group, which can then be used to make fabrics. In practice, the majority of yarns are made inone of four ways:twisting a number of(short) fibers together, twisting a number of (long) filaments together, laying a number of (long) filaments together withouttwist, or twistingor not twistinga single (long) filamentto producea monofilament (thread). Yarn should be strong, flexible,and elastic so thatit can be braided, knotted, interlaced, or looped as it is processed by various methods into a fabric. A system of producing tightly twisted yarns results in worsted yarn that is firmer and smoother than regular yarn. Yarns are often made by blending two or more differ - ent fibers to combine the strong points of each. When a manufactured yarn is texturized the long, plain,uniform yarn is changed to exhibit bulk, loft, and three- dimensional appearance. Stretchability may also be included. Yarns are curled, crimped, and twisted when texturized. Textile Production The major textile production methods are weaving and knitting. Minor methods produce braids, nets, lace, tufted carpets, and other products. The only fabrics made which do not use yarn are those nonwoven fabrics made directly from fibers before they are processed into yarn. Felt is the traditional nonwoven product. Textiles can be classified by their weave or structure. The value of a textile depends on many factors, primarily the quality of the raw material; the characteristics of the fiber/yarn; smoothness, hardness, and texture; fine, medium, or coarse fibers/yarn; density of yarn twist and density of weave; dyes/colors and pattern; and finishing processes. Woven Fabric A major method for producing fabrics is weaving, in which yarns are interlaced at right angles to each other. Thismethod was used by theancient Egyptians. Weaving continued to bedone by hand as amanual labor taskuntil machines weredeveloped during the In- dustrial Revolution. The invention of the flying shut- tle and the steam-powered loom in the 1700’s were major contributors to automating the weaving process. Three basic types of weaves are plain, twill, and satin. There can be variations within each of these three weaves. Besides the type of weave and the yarn types used, another variation of the weaving process is how close together the yarns are interlaced. Knitted Fabric Knitted fabrics are formed by continuously inter- looping one or more yarns. The knitting process may have been used tomake fabrics as early as the firstcen- tury. Knitting remained a hand labor skill until the eighteenth century,when powered knitting machines were developed. Various knitting processes within the basic weft knit type include plain knit, purl knit, rib knit, and in - terlock stitch. Weft knits are produced by machine Global Resources Textiles and fabrics • 1213 and by hand. The warp knitting process uses a ma - chine in which many parallel yarns are interconnected simultaneously to form loops in the lengthwise direc- tion. Within the basic warp type process, tricot knitting and raschel knitting are two methods used. Spe- cial processes that are variations of the two basic methods, sometimes in combination with special yarns, produce double knits, high pile knits, Jacquard knits, full-fashioned knits, textured knits, stretch knits, and bonded knits. Finishes Finishes are the treatments given to fibers, yarns, or fabrics to improve their basic characteristics. The three types of finishes employed are mechanicaltreat- ments, heat treatments, and chemical treatments. It is common for one or more of these treatments to be applied to practically every fabric produced. They change the appearance of the product, as in its look or feel, and/or add a functional characteristic such as waterproofing or flameproofing. Brushes, rollers, and hammers may be used in mechanical treatments. Heat-setting of thermoplastic material is a common heat treatment. Chemicals such as acids, bases, bleaches, polymers, and reactive resins are used to chemically change the characteristics of a material. The aesthetic finishes, by process name, include bleaching, brushing and shearing, calendering, car- bonizing, crabbing, decating, fulling, glazing, mer- cerizing, napping and shearing, scouring, singeing or gassing, sizing, andtentering. The functional-type finishes make textiles abrasion resistant, antibacterial, antisoil and antistain, antistatic, durable press (per- manent press), flame/fire retardant/resistant, moth repellent, permanently crisp, shrink resistant, water- proof, water repellent, or wrinkle resistant. Fabric Design The major elements of fabric design are the visual (how it looks) and the tactile (how it feels). All colors can be applied in an unending combination of pat- terns and designs. The feel of the fabric can be varied by the typesof yarn used,the fabrication method, how the color pattern is applied, and the types of finishes used. Dyeing and printing are two major methods of applying a pattern, color, or both, to afabric. Dyes can be applied to fiber, yarn, or fabric. Color can be applied by at least three methods: directly, the discharge method, and the resist or reserve method. Printing is typically done by methods such as roller printing, block printing, toiles de Jouy, stencil, screen printing, spray printing, electroplating, and by hand. The Textile Industry The textile industry is dynamic, with new processes, techniques, and methods constantly being developed. Sometimes they add to, and sometimes they replace, previous ways of operating. The idea of evolution and change canbe applied toall parts of theindustry,such as raw material and fiber development; yarn production technique; fabrication method; finishing technology; and the printing, dyeing, and design processes. The primary goal of all research and development is to sell a product attractive to consumers. Consumer research is an important factor in determining what the public wants, thereby helping to drive and focus the technology in particular directions. Federal laws govern textile labeling and product advertising, and the industry has developed voluntary self-regulating product quality and testing standards. Robert J. Wells Further Reading Albers, Anni. On Weaving. Reprint. New York: Dover Publications, 2003. Collier, Billie J., Martin Bide, and Phyllis G. Tortora. Understanding Textiles. 7th ed. Upper Saddle River, N.J.: Pearson Prentice Hall, 2009. Elsasser, Virginia Hencken. Textiles: Concepts and Prin- ciples. 2d ed. New York: Fairchild, 2005. Gale, Colin, and Jasbir Kaur. The Textile Book. New York: Berg, 2002. Harris, Jennifer,ed. Textiles, Five Thousand Years: An In- ternational History and Illustrated Survey. New York: H. N. Abrams, 1993. Jerde, Judith. Encyclopedia of Textiles. New York: Facts On File, 1992. Kadolph, Sara J. Textiles. 10th ed. Upper Saddle River, N.J.: Pearson Prentice Hall, 2007. Stout, Evelyn E. Introduction to Textiles. 3d ed. New York: Wiley, 1970. Tortora, Phyllis G., ed. Fairchild’s Dictionary of Textiles. 7th ed. New York: Fairchild, 1995. Wilson, Kax. A History of Textiles. Boulder, Colo.: Westview Press, 1979. See also: Agronomy; Animal breeding; Cotton; Flax; Hemp; Industrial Revolution and industrialization; Livestock and animal husbandry; Plant fibers; Renew - able and nonrenewable resources. 1214 • Textiles and fabrics Global Resources Thailand Categories: Countries; government and resources Thailand consistently exports the most rice in the world, is second internationally in tungsten production, and third globally in the amount of tin and rubber produced. These indigenous resources regularly se- cure income from worldwide markets, especially Asia, that demand those raw materials for manufacturing and nutritional purposes because of their quality and desired characteristics. The Country Thailand, located in southeastern Asia, borders four countries: Cambodia, Laos, Myanmar (Burma), and Malaysia. In 2007, Thailand had the thirty-eighth larg- est economy internationally. Its diverse terrain includes mountains, valleys, plains, and the Khorat Pla- teau. A peninsula extends south from southwestern Thailand. Several rivers flow through Thailand, most notably the Chao Phraya. Numerous islands are adjacent to Thailand’s coasts on the Gulf of Thailand and the Andaman Sea. National parks provide sanctuaries for wildlife and plants. Thai trade relies on ports host- ing international shipping, particularly at Laem Chabang in Chon Buri Province. Thailand is divided administratively into seventy-six provinces. Economically, Thailand underwent industrialization in the late twentieth century. Exports of mineral and agricultural resources, totaling more than $105 billion yearly, have bolstered the country’s economic growth. In the early twenty-first century, political tur- moil occasionally disrupted Thailand’s economy and exporting activities. Tungsten Thailand’s tungsten industry began in the 1940’s, after deposits of that mineral were located in northern Thai provinces. Tungsten, which has the high- est melting point for metals, provides industries a hard, heat-tolerant resource that has properties desired for electronics and tools. Tungsten is usually located in compounds with other elements. Wolfram- ite and scheelite mineral deposits, common in Thai- land’s mountainous terrain, provide the most Thai tungsten resources. Tungsten has been extracted from the Bilauktaung Range adjacent to Thailand’s south - western border with Myanmar (Burma). During the 1960’s, tungstenbecame a significant export resource for Thailand to acquire income from global markets, and Thailand attained a ranking of eighth internationally for quantity of tungsten produced. By 1970, Thai miners had started extracting tungsten from wolframite deposits in southern Thailand’s Nakhon Si Thammarat Province. With approximately 6,800 metric tons of tungsten yearly, Thailand produced the third most tungsten in the world. In the early 1980’s, Thailand’s tungsten production experi- enced low prices because of competition from China, which dominated the global tungsten market. As a re- sult, most Thai tungsten mines were closed. Near ChiangMai in thenorth, geologists identified deposits at Mae Lama, Mae Chedi, and Doi Ngom. In- vestors Amanta Resources Ltd. and Mae Fah Mining Ltd. reinvigorated Thai tungsten mining activity in the twenty-first century when the Lanna Tungsten Project focused on those deposits’ resources. The Doi Mok, Samoeng, and Khao Soon deposits secured other mining interests. By 2002, Thailand was producing and exporting ample amounts of tungsten globally, ranking second in tungsten production and retaining that ranking for several years. In 2006, Thailand produced 180 metric tons of tungsten, with prices reach- ing as high as $26,500 for a metric ton of tungsten. Rubber Thailand’s tropical climate helps rubber trees thrive, especially in southern provinces on the peninsula. Rubber tree plantations enable Thailand to export consistently sufficient amounts of natural rubber; in 2007, Thailand ranked third in the world for production of that resource. Malaysia and Indonesia usually produce more rubber than Thailand. Ten percent of Thai rubber is produced in Narathiwat and Pattani Provinces, with Surat Thani Province farmers producing the most. Tappers can extract 151 liters of latex sap daily per five hundred rubber trees tapped. Thai farmers acquire approximately 1.6 metric tons of natural rubber per hectare of rubber trees in a year. In 1991, Thailand rubber plantations first pursued production for international trade, expanding rubber sales to more foreign markets in the following years. Thailand produced about 2 million metric tons of rubber in 1999, which represented 34 percent of rubber production internationally. By the early twenty-first century, 90 percent of Thailand’s rubber was exported. In 2003, Thai rubber farms produced 2.58 million metric tons of that resource and exports Global Resources Thailand • 1215 . westerners during an era of economic duress, its implementation was relatively free of con - troversy, but several critics of its authority soon ap - 1208 • Taylor Grazing Act Global Resources peared Global Resources opment, nuclear energy research, conservation of natural resources, and many other projects have been part of the work of the Tennessee Valley Authority. Glenn L. Swygart Web Site Tennessee. practice, the majority of yarns are made inone of four ways:twisting a number of( short) fibers together, twisting a number of (long) filaments together, laying a number of (long) filaments together